Why am I so emotionally cold?

I'll never know why but I can be the most warm hearted person and also the coldest.. depending on how you treat me... long story short I had a "thing" with a guy not even a real relationship but after things didn't work out he tried to make me jealous by texting me saying he was with bae etc.. I've been acting so cold and distant but i don't exactly know where it's coming from..#virgoproblems